1. Technical Field
The present invention relates to a calorimetric sensor in which a receptor is immobilized on polydiacetylene supramolecule and, more particularly, to biochemical analysis using the same.
2. Discussion of Related Art
A general quantitative analysis utilizing an antibody includes enzyme immunoassay (EI), enzyme-linked immunosorbent assay (ELISA) and radio immunoassay (RIA). Of these, ELISA is a method that an enzyme is linked to an antibody and then an antigen-antibody reaction is identified. ELISA is now widely used since it is relatively simple and inexpensive, and is available to massive analysis. Particularly, ELISA is increasingly employed since it has a great advantage in that it has a sensitivity equal to that of RIA, but does not use radioactivity. However, ELISA has disadvantages in that it requires more samples in analysis, it takes long time, and it must undergo several steps. Further, although RIA has the highest sensitivity, it has a problem of danger due to radioactive materials.
Recently, in order to solve such problems, there have been suggested analytical methods that employ an isotope, fluorescence or an enzymatic reaction, and can convert a signal. However, of these methods, the method employing an isotope has a problem in safety, the method employing an enzymatic reaction has narrow analytical range and thus is not suitable for analyzing a sample in various concentration, and the method employing fluorescence has a problem that expensive fluorescent material must be again bound to a detected protein. In order to solve such problems, a label-free detecting method, for example, a method employing polydiacetylene, was suggested.
Polydiacetylene refers to a polymer of diacetylene monomers having alternate triple bonds. It is known that diacetylene forms a supramolecule such as a liposome, a langmuir-blodgett (LB) or langmuir-schaeffer (LS) single molecular membrane in an aqueous solution due to its amphoteric property. When the diacetylene constituting a supramolecule is exposed to UV light at 254 nm, polymerization between adjacent diacetylenes occurs and thus the diacetylene becomes blue. Further, when a polymerized polydiacetylene supramolecule is stimulated by temperature, pH, friction, a surfactant or a solvent, etc., its color is transited into red one. Polydiacetylene color transition is dependent on the length of π-conjugation in a polymeric bond, and a structure of the resulting molecule. Accordingly, various types of sensors can be prepared by employing the change in a polydiacetylene polymeric bond. For example, a biosensor capable of detecting an influenza virus, a cholera toxin, or E. coli, etc. can be prepared by introducing chemically a molecule capable of binding specifically to a cell or a protein into a terminal group of a diacetylene or other lipid molecule, and then mixing it with other diacetylene to form a liposome. However, the polydiacetylene biosensor has a disadvantage in that a lipid molecule having receptor function must be newly synthesized depending on an analyte.
Thus, the present inventors completed the present invention by preparing a polydiacetylene supramolecule with use of a diacetylene-maleimide molecule capable of reacting quickly and selectively with thiol, selecting an antibody or other receptor suitable for an analyte and immobilizing it on the polydiacetylene, and then reacting it with a sample containing an antigen or a ligand thereby confirming color transition of the polydiacetylene supramolecule.